# C program to calculate compound interest

This program will read principal, rate and time in years and then print compound interest on entered principal for given time period.

## Compound Interest

Compound interest is the amount in which interest is added into the principle so that interest also can be earned interest with the principle.

## Compound Interest Formula

The formula to get compound interest is:

```compound_interest=principal*((1+rate/100)time-1)
```

## Calculate Compound Interest using C program

```/*C program to calculate compound interest.*/

#include <stdio.h>
#include <math.h>

int main()
{
float principal, rate, year, ci;

printf("Enter principal: ");
scanf("%f", &principal);

printf("Enter rate: ");
scanf("%f", &rate);

printf("Enter time in years: ");
scanf("%f", &year);

// calculate compound interest

ci = principal * ((pow((1 + rate / 100), year) - 1));

printf("Compound interest is: %f\n", ci);

return 0;
}
```

### Output

```Enter principal: 10000
Enter rate: 10.25
Enter time in years: 5
Compound interest is: 6288.943359
```